title: Fast optical source for quantum key distribution based on semiconductor optical amplifiers.
abstract: A novel integrated optical source capable of emitting faint pulses with different polarization states and with different intensity levels at 100 MHz has been developed. The source relies on a single laser diode followed by four semiconductor optical amplifiers and thin film polarizers, connected through a fiber network. The use of a single laser ensures high level of indistinguishability in time and spectrum of the pulses for the four different polarizations and three different levels of intensity. The applicability of the source is demonstrated in the lab through a free space quantum key distribution experiment which makes use of the decoy state BB84 protocol. We achieved a lower bound secure key rate of the order of 3.64 Mbps and a quantum bit error ratio as low as 1.14×10⁻² while the lower bound secure key rate became 187 bps for an equivalent attenuation of 35 dB. To our knowledge, this is the fastest polarization encoded QKD system which has been reported so far. The performance, reduced size, low power consumption and the fact that the components used can be space qualified make the source particularly suitable for secure satellite communication.
authors.affiliation: ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, Barcelona, Spain. marc.jofre@icfo.es
authors.forename: M
authors.initials: M
authors.lastname: Jofre
authors.forename: A
authors.initials: A
authors.lastname: Gardelein
authors.forename: G
authors.initials: G
authors.lastname: Anzolin
authors.forename: W
authors.initials: W
authors.lastname: Amaya
authors.forename: J
authors.initials: J
authors.lastname: Capmany
authors.forename: R
authors.initials: R
authors.lastname: Ursin
authors.forename: L
authors.initials: L
authors.lastname: Peñate
authors.forename: D
authors.initials: D
authors.lastname: Lopez
authors.forename: J L
authors.initials: JL
authors.lastname: San Juan
authors.forename: J A
authors.initials: JA
authors.lastname: Carrasco
authors.forename: F
authors.initials: F
authors.lastname: Garcia
authors.forename: F J
authors.initials: FJ
authors.lastname: Torcal-Milla
authors.forename: L M
authors.initials: LM
authors.lastname: Sanchez-Brea
authors.forename: E
authors.initials: E
authors.lastname: Bernabeu
authors.forename: J M
authors.initials: JM
authors.lastname: Perdigues
authors.forename: T
authors.initials: T
authors.lastname: Jennewein
authors.forename: J P
authors.initials: JP
authors.lastname: Torres
authors.forename: M W
authors.initials: MW
authors.lastname: Mitchell
authors.forename: V
authors.initials: V
authors.lastname: Pruneri
mesh_terms: D000669:Amplifiers, Electronic; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation*; D053844:Lasers, Solid-State; D008029:Lighting / Q000295:instrumentation*; D012031:Refractometry / Q000295:instrumentation*; D012637:Security Measures